The invention relates to a fuel feed unit for a motor vehicle having a fuel pump which is driven by an electric motor, and having a rotor of the fuel pump arranged between two housing parts, the rotor being fastened in a rotationally fixed manner to a shaft of the electric motor.
Fuel feed units of this type are frequently used in modern-day motor vehicles and are known from practice. The housing parts of the fuel pump are produced mainly from metal or a sintered ceramic, or have a sintered bush, which is pressed into plastic, as a bearing for the shaft. The housing parts are separated from the rotor by a particularly small clearance and thus form a gap seal of the fuel pump. Heat input as a result of friction or heat from the electric motor leads, however, to the housing parts and the rotor expanding, and thus to a reduction in the gap between the housing parts and the rotor. As a result, further friction occurs in the fuel pump which, in the worst case, causes the later to become jammed. The fuel pump seizes after a very short time in particular during dry running of the fuel feed unit.
The problem on which the invention is based is that of developing a fuel feed unit of the type mentioned in the introduction in such a way that the fuel pump is largely prevented from seizing, in particular during dry running.